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Biomedical subjects

E Stern

Publications and source records attributed to E Stern.

At least 55 records · Page 3Linked to original sources
PubMed1996

Functional neuroimaging of hallucinations in schizophrenia: toward an integration of bottom-up and top-down approaches.

Hallucinations in schizophrenia represent an important clinical problem, an interesting neuropsychological enigma, and a significant challenge for neuroscientific research. Functional neuroimaging techniques allow the in vivo, systems-level study of brain dysfunction underlying this debilitating symptom. Clinical and scientific vantage points that can inform the design and interpretation of functional neuroimaging studies of schizophrenic hallucinations are outlined. These include considerations of the phenomenology of hallucinations, the relationship of hallucinations to other symptoms of schizophrenia, and the neuropsychological functions that are thought to be disrupted in hallucinations. They also include the anatomical and chemical brain systems in which abnormalities are implicated in schizophrenia, the neurologic conditions in which hallucinations may occur, the neurochemical contexts that are associated with hallucinations, and the methodologic details of the functional neuroimaging techniques employed. Bottom-up and top-down functional neuroimaging strategies for the investigation of schizophrenic hallucinations with positron emission tomography (PET), single photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI) are reviewed. Bottom-up approaches start with or measure the biology associated with hallucinations. Top-down approaches start from the specific neuropsychological dysfunctions thought to be associated with hallucinations. The distributed brain regions, systems and functions implicated in schizophrenic hallucination formation are then discussed in the context of an integration of bottom-up and top-down approaches. Focus is placed upon abnormalities in the functions of, and interactions among, auditory-linguistic association cortices, caudal and rostral limbic/paralimbic systems, prefrontal cortices, ventral striatum and (non-specific projection and associative) thalamic nuclei, as well as upon the glutamatergic, GABAergic and ventral tegmental dopaminergic modulation of these systems.

Brain Mapping↗
PubMed1995

A functional neuroanatomy of hallucinations in schizophrenia.

Hallucinations, perceptions in the absence of external stimuli, are prominent among the core symptoms of schizophrenia. The neural correlates of these brief, involuntary experiences are not well understood, and have not been imaged selectively. We have used new positron emission tomography (PET) methods to study the brain state associated with the occurrence of hallucinations in six schizophrenic patients. Here we present a group study of five patients with classic auditory verbal hallucinations despite medication, demonstrating activations in subcortical nuclei (thalamic, striatal), limbic structures (especially hippocampus), and paralimbic regions (parahippocampal and cingulate gyri, as well as orbitofrontal cortex). We also present a case study of a unique, drug-naive patient with visual as well as auditory verbal hallucinations, demonstrating activations in visual and auditory/linguistic association cortices as part of a distributed cortical-subcortical network. Activity in deep brain structures, identified with group analysis, may generate or modulate hallucinations, and the particular neocortical regions entrained in individual patients may affect their specific perceptual content. The interaction of these distributed neural systems provides a biological basis for the bizarre reports of schizophrenic patients.

Adult↗
PubMed1995

The functional anatomy of recovery from auditory agnosia. A PET study of sound categorization in a neurological patient and normal controls.

H2(15)O-PET was used to investigate the functional anatomy of recovery in a patient (J.B.) with bilateral perisylvian strokes and auditory agnosia, who partially regained the ability to recognize environmental sounds, but remained clinically word-deaf. The patient and a group of six normal volunteers were scanned in the following three conditions: (i) passive listening to environmental sounds; (ii) categorization of environmental sounds; (iii) at rest. In normal subjects, passive listening as compared with rest was associated with significant activations in the auditory cortices and posterior thalami, and in the inferior parietal lobe and anterior insula/frontal opercular region on the right. In J.B., activations were observed in the spared auditory cortex and inferior parietal lobe of the right hemisphere and in regions adjacent to the perisylvian lesion in the left hemisphere (anterior insula/frontal opercular region, middle temporal gyrus and inferior parietal lobe). The recovered function, as measured by categorization of sounds compared with passive listening, in J.B. was associated with bilateral activation of a distributed network comprising (pre)frontal, middle temporal and inferior parietal cortices, as well as the right cerebellum and the right caudate nucleus. In addition, there was a left-sided activation of the anterior cingulate gyrus. In normal subjects, the same categorization task led to activation of a network comprising (pre)frontal, middle temporal and inferior parietal cortices in the left hemisphere only. These results suggest that bilateral activation (with recruitment of areas homologous to those known to be responsible for normal function), the engagement of peri-infarct regions, and the involvement of a more widespread neocortical network, are mechanisms of functional reorganization after injury that may enable recovery from, or compensation for, cognitive deficits.

Agnosia↗
PubMed1994

Imaging transient, randomly occurring neuropsychological events in single subjects with positron emission tomography: an event-related count rate correlational analysis.

Many neuropsychiatric symptom states are idiosyncratic, involuntary, randomly occurring, subjective, and transient. The brain states associated with these clinically important mental states cannot be imaged directly with existing positron emission tomography (PET) techniques. A new PET method that brings such mental/brain states under experimental control for analysis in single subjects is described. It utilizes a slow bolus H2 15O three-dimensional (3D) regional CBF imaging technique. The analysis focuses upon natural or experimentally induced variance in the temporal distribution of specific neuropsychological events over the course of a study session. For each scan, the amount of radioactivity entering the brain during these events is calculated to derive a score reflecting the contribution of the events to the image. A statistical analysis is then performed to identify those pixels in which the intensity covaries with the scan scores over the subject's scans. This permits the identification of the brain areas associated with the mental state of interest. The method is validated using an auditory sentence-monitoring task. The detection in single subjects of cerebral activations associated with recurrent events as brief as 2 s in duration is demonstrated. This method may be used as a means of imaging ephemeral neurologic or neuropsychiatric symptom states or as an alternative to a subtraction design for activation studies.

Adult↗
PubMed1993

Detection of thirty-second cognitive activations in single subjects with positron emission tomography: a new low-dose H2(15)O regional cerebral blood flow three-dimensional imaging technique.

Positron emission tomography regional CBF (rCBF) studies of cognitive processes have traditionally required 30-60 mCi of H2(15)O per scan and intersubject averaging to achieve statistical significance. However, intersubject anatomical, functional, and disease variability can make such an approach problematic. A new method that produces significant results in single subjects is presented. It is based upon high-sensitivity three-dimensional imaging and a "slow" bolus administration of < 15 mCi of H2(15)O per scan. The method is validated in four normal volunteers using control and auditory-language activation tasks with four scans per condition and statistical parametric mapping analysis. It is demonstrated that the rCBF distribution associated with the cognitive state is detected during the arrival of radiotracer in the brain. This occurs over 30 s and constitutes a critical temporal window during which stimulation should be performed. A 90-s acquisition time is found to produce results of greater significance than a 60-s acquisition time. The implications of the results and the functional neuroanatomical findings are discussed. This method is suitable for the study of individual functional neuroanatomy in many neuropsychological, pharmacologic, and symptom states in normal subjects and in patients with psychiatric and neurologic disorders.

Adult↗
PubMed1992

A few points.

Explore the source record for details and available documents.

Education, Nursing↗
PubMed1990

Imaging of prenatally detected intra-abdominal extralobar pulmonary sequestration.

Intra-abdominal extralobar pulmonary sequestration is a rare congenital anomaly which may present as an abdominal mass. We describe a case of intra-abdominal extralobar pulmonary sequestration detected prenatally as a left suprarenal mass. The ultrasound, computed tomography and magnetic resonance imaging findings are illustrated and correlated with the pathologic findings.

Adult↗
PubMed1990

Continuous nebulization of albuterol (salbutamol) in acute asthma.

We studied the safety and efficacy of albuterol (salbutamol) delivered by continuous nebulization (CN) in the initial emergency department treatment of asthma. In a randomized fashion 21 patients received 5 mg of albuterol by bolus nebulization (BN) at time 0 and again 60 minutes later. Twenty-one others received albuterol (0.2 mg/ml) by CN using a calibrated nebulizer with a known output of 25 ml/h. Thus, each patient had received 10 mg of albuterol over two hours. FEV1, blood pressure (BP), heart rate (HR), respiratory rate (RR), and hand tremor were recorded at 30-minute intervals. The FEV1 was 1.48 +/- 0.64 L prior to BN and increased to a maximum of 2.20 +/- 0.94 L (p less than 0.05) 90 minutes later. The FEV1 prior to CN was 1.13 +/- 0.51 L and improved to 2.20 +/- 1.02 L (p less than 0.05) at 120 minutes. The FEV1 did not differ significantly between regimens over the 2-hour period. Both modes of therapy were well tolerated. There was a slight but significant increase in HR at 30 and 90 minutes in the BN group when compared with CN. There was no significant difference in BP, RR, or tremor between the groups. Thus, albuterol by CN was found to be equally effective as the same medication by BN in the early treatment of asthma in patients seen in the emergency department.

Acute Disease↗
PubMed1990

Lung hernia: radiographic features.

Lung hernia is an abnormal protrusion of the lung beyond the confines of the thoracic cage. Hernias are classified as cervical, intercostal, or diaphragmatic. Each of these types can be either congenital or acquired. Acquired hernias can be spontaneous, posttraumatic, or pathologic as a result of a neoplastic or inflammatory process. This report describes five cases of lung hernias. Two were congenital cervical hernias, detected as incidental findings on chest radiographs of infants. One was a posttraumatic intercostal hernia detected on a chest radiograph and confirmed with CT. The remaining two were acquired intercostal hernias at the site of prior chest-tube drainage of tuberculous empyemas. Although both of these were clearly shown on CT scans, only one was visible on chest radiographs.

Aged↗
PubMed1989

Genotype-treatment interaction in response of mice to early barbiturate administration.

Results of this investigation show a differential effect of early barbiturate administration on behaviors of mice of two inbred strains in the open field and in the barrier cage. Pups of the inbred strains DBA/l and C57BL/10 were fostered by HS/Ibg dams and were given a daily injection of 50 mg/kg sodium phenobarbital on postnatal days 2-21 (treated groups); control pups received vehicle injections. At 28 and 30 days the animals were tested in an open field and in a barrier cage. The DBA/l mice responded differently from C57BL/10 to early barbiturate treatment. Treated DBA/l mice showed a marked reduction from control levels in open-field locomotion and grooming but not in defecation. In the barrier test, there were reductions in jumping, peeking and grooming and increase in defecation. The differences between controls and treated in the C57BL/10 strain were small except for barrier jumping and peeking. It is suggested that genotype (strain) - environment (drug) interaction exists for the effect of early phenobarbital administration on behavior: DBA/l was sharply affected by the drug, while the behavior of C57BL/10 was little altered by neonatal phenobarbital administration.

Animals↗
PubMed1989

The protracted effect of o,p'-DDD in Cushing's disease and its impact on adrenal morphogenesis of young human embryo.

We hereby present a patient with Cushing's disease who became pregnant while being treated with o,p'-DDD and underwent a therapeutic abortion in view of the known embryotoxicity and placental transfer of this drug. Biopsy of adipose tissue in this patient showed it to be the storage site of considerable quantities of o,p'-DDD. Serum levels of o,p'-DDD determined in this patient initially four months after withdrawal of treatment and in another similar case three months after withdrawal were about 20 times higher than those found in untreated patients and reached control values only about 20 months later. Repeated evaluation of plasma and urinary free cortisol failed to reveal any correlation with the serum levels of o,p'-DDD, suggesting that the drug blood values cannot be used as a reliable indicator of the therapeutic effect on the adrenal gland. The histopathological examination of the embryo, aged about 42 days, revealed a dysmorphogenic event in the cortical primordia characterized by pycnotic sympathoblasts. It is suggested that such a toxic effect of o,p'-DDD on the embryonic cortical cells may act indirectly, affecting the viability of the migrating sympathoblasts.

Abortion, Therapeutic↗
PubMed1988

Prevalence of diabetes in Israel. Epidemiologic survey.

A survey of 4660 Israeli adults aged 30-65 yr revealed an overall diabetes prevalence of 4.1%. Prevalence was slightly lower in women (3.5%) than in men (4.3%), rose with age, and was highest in the group greater than 60 yr old (10.3%). In approximately 40% of the diabetic subjects, the diagnosis of diabetes was made as a result of the screening program. Association with a family history of diabetes, obesity, and the presence of other diseases was greater in diabetic than in nondiabetic subjects. The prevalence of diabetes differed among different segments of the survey population when classified according to country of origin, being lowest in African and Asian (1.2%), intermediate in American and European (4.9%), and highest in Israeli born (5.5%); this order of prevalence is the reverse of that reported in earlier surveys. The results indicate that the overall diabetes prevalence in Israel, and that within the European- and American-born segment, is comparable to that reported in other westernized societies. The findings also suggest that environmental factors contribute to the phenotypic expression of the non-insulin-dependent genotype(s) but that the influence of such factors varies with different genetic backgrounds.

Adult↗